SAN DIEGO, CA -- New research suggests that drinking sweetened beverages, especially diet drinks, is associated with an increased risk of depression in adults while drinking coffee appears to slightly lower that risk.

"Sweetened beverages, coffee and tea are commonly consumed worldwide and have important physical -- and may have important mental -- health consequences," said study author Dr. Honglei Chen of the National Institutes of Health and a member of the American Academy of Neurology. The study, supported by the National Institutes of Health, the National Institute of Environmental Health Sciences and the National Cancer Institute, will be presented at the American Academy of Neurology's 65th annual meeting in San Diego in March.

It involved 263,925 people between the ages of 50 and 71 at enrollment. From 1995 to 1996, researchers evaluated their consumption of drinks such as soda, tea, fruit punch and coffee. About 10 years later, the researchers asked the participants whether they had been diagnosed with depression since the year 2000. A total of 11,311 depression diagnoses were made.

People who drank more than four cans or cups per day of soda were reportedly 30% more likely to develop depression than those who drank no soda. Those who drank four cans of fruit punch per day were about 38% more likely to develop depression than those who did not drink sweetened drinks, according to the study.

The risk appeared to be greater for people who drank diet rather than regular soda, diet fruit punches versus regular, and diet versus regular iced tea.

Meanwhile, people who drank four cups of coffee per day were about 10% less likely to develop depression than those who drank no coffee.
"Our research suggests that cutting out or down on sweetened diet drinks or replacing them with unsweetened coffee may naturally help lower your depression risk," said Chen. She added that more research is needed to confirm the findings.